Vascular endograft

ABSTRACT

An endograft for a vessel having a vascular branch extending from the vessel is provided. The endograft includes a main body having a wall separating interior and exterior surfaces and adapted to be inserted within the vessel. The main body is characterized by a single proximal opening and two distal openings and at least one aperture extending through the wall. At least one stent is secured to the main body that upon expansion pressure fits the main body into the vessel. An open tunnel is secured to the interior surface of the main body around the main body aperture and secured somewhere along the tunnel length to provide fluid communication between the interior and exterior surfaces of the main body through the aperture and with the vascular branch in proximity to the main body aperture. The tunnel is readily formed independent of an expandable stent. Through the addition of further apertures and tunnels, an endograft is well suited for revascularizing the celiac, superior mesenteric artery and renal arteries for the treatment of a suprarenal aortic aneurysm. The insertion of a sleeve positioned partly within the tunnel and extending beyond the exterior surface of the main body into the vascular branch assures continued fluid flow to the vascular branch. The two distal openings are adapted to engage the iliac arteries.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Utility applicationSer. No. 11/337,303 filed Jan. 23, 2006, which claims prioity of U.S.Provisional Patent Application Ser. No. 60/653,793 filed Feb. 17, 2005,which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention in general relates to a vascular endograft andmethod for surgical deployment thereof, and in particular to a vascularendograft facilitating revascularizing branching vessels.

BACKGROUND OF THE INVENTION

Stent grafts have become a popular treatment option for aneurysms.Typically, a stent graft is delivered to a treatment site throughendovascular insertion via an introducer or catheter. Subsequent radialexpansion retains the graft in position relative to the vessel wall. Ininstances where an aneurysm is located along a length of vessel on whichbranch vessels are not present, a simple tubular cylindrical stent graftis suitable. Additionally, stent grafts are known to the art fortreatment of aneurysms in aortic regions where the distal end of thegraft bifurcates to define two lumens so as to extend into arterialbranches. Such bifurcated stent grafts are well known for the treatmentof ascending thoracic and abdominal aortic aneurysms. Exemplary stentsof this kind are embodied in U.S. Pat. Nos. 6,695,875 B2 and 6,814,752B1 and U.S. Patent Application Publication 2004/0230287 A1.

Currently, aneurysms in certain anatomic regions of the aorta haveproved difficult to properly repair with a stent graft. In particular,treatment of suprarenal aortic aneurysms has proved problematic. In suchlocales, the lack of a neck above the aneurysm precludes attachment of aconventional endovascular graft. Additionally, in the treatment of ananeurysm in such a locale, the preoperative measurement of arterial andaortic dimensional variables necessary to form a suitable endograft hasproven to be complex. Any misfit in preparing a conventional stent graftto treat an aneurysm in this region results in lumenal obstruction orcollapse, or material fatigue, resulting in continued blood flow intothe aneurysm.

WO 03/082153, FIGS. 7-11, is representative of the stent grafts for thetreatment of suprarenal aortic aneurysms. This graft includes a singlelumen containing a Gianturco type zigzag Z stent tube in communicationat a distal end with an aperture in the lumen and free floating at theproximal end within the lumen. Unfortunately, the free-floating tubeproximal end is prone to damage during insertion of a sleeve therefrominto an artery in registry with the aperture, as well as underhemodynamic operating conditions.

Thus, there exists a need for a vascular endograft capable of treatingan aneurysm in a vessel having adjacent vessel branches.

SUMMARY OF THE INVENTION

An endograft for a vessel having a vascular branch extending from thevessel is provided. The endograft includes a main body having a wallseparating interior and exterior surfaces and adapted to be insertedwithin the vessel. The main body is characterized by a single proximalopening and two distal openings and at least one aperture extendingthrough the wall. At least one stent is secured to the main body thatupon expansion pressure fits the main body into the vessel. An opentunnel is secured to the interior surface of the main body around themain body aperture and secured somewhere along the tunnel length toprovide fluid communication between the interior and exterior surfacesof the main body through the aperture and with the vascular branch inproximity to the main body aperture. The tunnel is readily formedindependent of an expandable stent. Through the addition of furtherapertures and tunnels, an endograft is well suited for revascularizingthe celiac, superior mesenteric artery and renal arteries for thetreatment of a suprarenal aortic aneurysm. The insertion of a sleevepositioned partly within the tunnel and extending beyond the exteriorsurface of the main body into the vascular branch assures continuedfluid flow to the vascular branch. The two distal openings are adaptedto engage the iliac arteries.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an inventive endograft depicted within apartial cutaway of the superior mesenteric and renal artery region ofthe descending aorta;

FIG. 2 is a top view of the inventive stent graft depicted in FIG. 1absent the expandable stents for visual clarity;

FIG. 3 is a magnified cross-sectional view through a tunnel connectingthe endograft depicted in FIG. 1 to the superior mesenteric artery andcontaining a sleeve therein;

FIG. 4 is a plan view of an inventive endograft proportioned andapertured for revascularization of the celiac, superior mesenteric, andtwo renal arteries, the tunnels are depicted interior to the endograftas dashed lines; the expandable Z stents are not shown for visualclarity;

FIGS. 5A-5D are a schematic depiction of a possible surgical process forrevascularizing celiac, superior mesenteric, and renal arteries, as partof the deployment of an inventive endograft to treat a suprarenal aorticaneurysm; and

FIG. 6 is a plan view of an inventive endograft proportioned to distallysecure to the right and left common iliac arteries.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention has utility as a vascular endograft well suitedfor the treatment of aneurysms. While the present invention is detailedherein with respect to an endograft having revascularization tunnelspositioned for use in the aortic region encompassing the superiormesenteric artery (SMA) and renal arteries, it is appreciated that aninventive endograft has application in a variety of vascular settingswhere vessels branch from a main lumen. In addition, the inventiveendograft is appreciated to be suitable for the treatment of an aneurysmalone, or in combination with a conventional stent graft depending uponthe relative position and size of a vascular aneurysm.

An inventive endograft has a main body including at least onedeployable, expanding stent and an open tunnel secured within the mainbody to a main body sidewall aperture to ensure reliable fluidcommunication between fluid passing through the main body and a vascularbranch overlying an open tunnel terminus. The tunnel is securedsomewhere along the tunnel length to the interior of the main body andlacks a stent expander along the length thereof. Preferably, the tunnelis secured to the main body along the majority of the tunnel length.Through the use of a sleeve that extends from the tunnel into theoverlying vascular branch, a predefined percentage of the fluid flowthrough the main body of an inventive endograft is shunted into thevascular branch. While an open tunnel used in an inventive endograft iscylindrical in general shape in a first embodiment, it is appreciatedthat a bifurcated tunnel having an inverted “Y” shape is operative insituations where vascular branch bifurcates proximal to the centralvessel are desired to have assured fluid flow.

The present invention is further illustrated with respect to thefollowing non-limiting embodiments depicted in the figures. Referringnow to FIGS. 1-3, an inventive endograft is shown generally at 10. Theendograft 10 has a main body 12 having at least one proximal opening 14and at least one distal opening 16. As used herein, it is appreciatedthat proximal and distal are defined relative to the direction of fluidflow through the vessel lumen in which an inventive endograft issecured. At least one stent 18 is secured about the circumference of themain body 12 on the external surface 20 of the main body wall 15. AGianturco zigzag stent is representative of stent types operativeherein. The main body 12 has an interior surface 22 through which fluidcommunication within the vessel is maintained. An open tunnel 24 has amouth 26 and a terminus 28. The tunnel 24 is formed of a material thatwill not become obstructed or collapse under prolonged exposure tophysiologic fluid transport. Materials suitable for the construction ofa main body 12 and a tunnel 24 independently in each case includepolymeric materials such as those sold under the trade names Dacran®,Gortex®, Teflon® and implant grade silicones. In order to precludeobstruction and/or collapse of a tunnel 24 subsequent to placement, thetunnel 24 is formed independent of an extendable stent associated withthe tunnel circumference. The terminus 28 of the tunnel 24 is sealedaround an aperture 30 within the main body 12 and is flush with theexterior surface 20. As a result, the tunnel 24 does not extend beyondthe dimensions of the main body 12; this attribute facilitates placementof an inventive endograft 10 within the central vessel denoted at V. Theaperture 30 and terminus 28 of the tunnel 24 are positioned within themain body 12 so as to overlie a vascular branch B extending from thevessel V in which the main body 12 is placed. The tunnel 24 is securedto the interior surface 22 at at least one point along the tunnellength. A single point securement is ideally proximal to the mouth 28.Preferably, the tunnel is secured along the majority of the tunnellength. More preferably, the entire tunnel length is secured to theinterior surface 22. Securement of the tunnel 24 to the interior surface22 is accomplished with conventional fastening techniques illustrativelyincluding sutures, contact adhesives, sonic welding, thermal welding,and combinations thereof. A securement anchoring the tunnel 24 to theinterior surface 22 is critical to the longevity of an inventiveendograft in assuring that the tunnel 24 does not kink during placementor under the strong pulsatile flow dynamics experienced within theaorta. It is appreciated that each vascular branch requiring perfusionthat overlies an inventive endograft is provided with an open tunnel asdescribed herein to assure fluid communication therewith.

With an inventive endograft 10 placed within a vessel V, fluidcommunication with a vascular branch B is provided through the placementof a separate sleeve 32 in part within the tunnel 24 and extendingbeyond the terminus 28 into the vascular branch B as shown in FIG. 3. Asleeve 32 is conventional to the art and typically is formed ofmaterials such as those used for the formation of the main body 12 orthe tunnel 24. A sleeve 32 typically includes multiple circumferentialstents 34 in order to retain the sleeve 32 in a preselected positionrelative to the tunnel 24 and the vascular branch B.

The inventive embodiment depicted in FIGS. 1-3 corresponds to anendograft spanning the suprarenal portion of the aorta and as such thevessel V is the aorta and the vascular branch B is the superiormesenteric artery. The additional vascular branches depicted at C and Dcorrespond to the right and left renal arteries, respectively. As bloodflow to the renal arteries C and D must necessarily be maintained in asuccessful aneurysm treatment, tunnel 24′ is placed within the main body12 in order to assure fluid communication between the aorta and theright renal artery C, where lice primed numerals correspond to thosedetailed above with respect to tunnel 24. Tunnel 24 is secured to theinterior surface 22 as detailed above with respect to tunnel 24. Theleft renal artery D is depicted with the uncommon phenotype of animmediate bifurcation in order to illustrate that a bifurcated tunnel 36optionally replaces a cylindrical tunnel as depicted with reference tonumeral 24 in instances where patient anatomy so dictates. Bifurcatedtunnel 36 has a mouth 38 of a preselected diameter and a bifurcation 40so as to define a first terminus 42 and a second terminus 44. Thetermini 42 and 44 are sealed to apertures 46 and 48 formed through thewall 15 of the main body 12. Tunnel 36 is secured to the interiorsurface 22 as detailed above with respect to tunnel 24. Sleeves 50 and52 are similar to sleeve 32 as described with respect to tunnel 24 andserve to assure a preselected percentage of blood flow to each of theleft renal arterial branches.

It is appreciated that the relative percentage of fluid exiting throughan inventive tunnel relative to the percentage of fluid exiting thedistal opening of an inventive endograft is controlled by the effectivediameter of the tunnel as compared to the endograft diameter at theposition of the tunnel mouth. The effective diameter of an inventivetunnel is appreciated to be equivalent to the internal diameter of thetunnel mouth in the theoretical instance where the tunnel wall andsleeve are Of infinitesimal thickness. Actual flow to a vascular branchis readily modeled with standard fluid dynamic equations. In theembodiment depicted in FIGS. 1-3, tunnels 24, 24′ and 36 have lengthsranging from 10 to 25 millimeters with each tunnel having a diameter offrom between 6 and 12 millimeters. The internal surface diameter at theproximal opening 14 is typically between 35 and 45 millimeters while theinternal diameter about the distal opening 16 ranges from 20 to 30millimeters. The overall length of the endograft 10 for an adult humanranges from 60 to 120 millimeters. While the above dimensional rangesassociated with an inventive endograft 10 are those associated with asuprarenal endograft for an adult human subject, it is appreciated thathuman child, veterinary endografts, as well as those used to treatdifferently positioned aneurysms within an adult human, or toaccommodate peculiar subject anatomy will vary in any, or all of thesedimensions.

An inventive endograft in addition to itself precluding fluid flow to ananeurysm is appreciated to be suitable for the joinder of a secondarystent 60 to the distal opening 16 thereof in order to function as ananchoring neck for a conventional stent graft. Joinder of a secondarystent 60 to an inventive endograft is accomplished through a variety oftechniques including the use of a vascular cuff 62.

In selecting an endograft for a particular individual, the principalvariables include measurement of the internal diameter of the vesselthat provides the outer diameter of an inventive endograft, as well asthe tunnel terminus internal diameter derived from a measurement ofvascular branch internal diameter. Compared to existing stent grafts,the present invention represents a simplification of the designmodifications and overall preoperative measurements associated withstent graft design.

The placement of an inventive endograft optionally results in thesacrifice of the celiac artery in the instance where the inventiveendograft is in a suprarenal position. While an inventive endograft isextended to provide a tunnel for the celiac artery, the celiac arterysacrifice is compensated for by continued flow through the superiormesenteric artery to prevent adverse events. Sacrifice of the celiacartery provides a considerably longer sealing zone proximal to mouth 26of the tunnel 24. The suprarenal endograft 10 depicted in FIGS. 1-3 isan indicated treatment for individuals with pararenal or suprarenalabdominal aortic aneurysms, as well as those individuals sufferingfailure of a conventional endograft repair secondary to aortic neckdeterioration.

An endograft maintaining flow to an overlying celiac artery is depictedin plan view generally at 70, where like numerals correspond to thosedetailed with respect to FIG. 1. The endograft 70 has tunnels 24 and 24′having termini 28 and 28′ that are spaced to overlie the aorticjunctions with the superior mesenteric and right renal arteries,respectively, upon implantation. Additional tubular tunnels 24″ and 24′″are provided with termini 28″ and 28′″ that are spaced to overlie theleft renal and celiac arteries, respectively, upon implantation. Each ofthe tunnels 24, 24′, 24″, and 24′″ has a mouth 26, 26′, 26″, and 26′″,and are secured to the interior surface of the main body wall 72, asdescribed with respect to FIGS. 1-3. A portion of the fluid entering theproximal opening 74 relative the direction of fluid flow through thevessel lumen in which an inventive endograft is secured is communicatedthrough the main body 12, past at least one stent 18 and into one of thetunnels 24, 24′, 24″, or 24′″ and expelled via one of the apertures 30,30′, 30″, or 30′″ extending through the main body wall 72. The fluid nottransiting the wall 72 is expelled via distal opening 76.

Referring now to FIG. 6, an inventive endograft is shown generally at200. Endograft 200 has a main body 202 having a proximal opening 204 anda bifurcated pair of distal openings 206 and 207. At least one stent 208is secured about the circumference of the main body 202 on the externalsurface 210 of the main body wall 205. A Gianturco zigzag stent isrepresentative of stent types operative herein. The main body 202 has aninterior surface 212 in which fluid communication within the vessel ismaintained. An open tunnel 214 has a mouth 216 and a terminus 218 withthe main body 202 and tunnel 214 being formed of materials as previouslydescribed with respect to FIGS. 1-3. The tunnel 214 is formedindependent of an extendable stent associated with the tunnelcircumference. Terminus 218 of the tunnel 214 is sealed around anaperture 220 within the main body 202 and is flush with the exteriorsurface 210. As a result, the tunnel 214 does not extend beyond thedimensions of the main body 202 so as to facilitate placement of theendograft 200 within a primary vessel. The aperture 220 and the terminus218 of the tunnel 214 are positioned within main body 202 so as tooverlie vascular branches to which blood flow must necessarily bemaintained upon placement of the main body 202. Tunnel 214 is secured tothe interior surface 212 at at least one point along the tunnel length.A single point securement is ideally proximal to the mouth 218.Preferably, the tunnel is secured along the majority of the tunnellength. More preferably, the entire tunnel length is secured to theinterior surface 212. Securement of the tunnel 214 to the interiorsurface 212 is accomplished with conventional fastening techniques asdetailed with respect to FIGS. 1-3. To facilitate fluid communicationbetween the interior 212, the endograft 200 and a vascular branchoverlying the aperture 220, a sleeve 222 is placed in part within thetunnel 214 and extending beyond the terminus 218 into the vascularbranch. The system is of a composition and form as previously describedwith respect to FIGS. 1-3. The endograft 200 has additional tunnels214′, 214″ and 214′″ with respective mouths 26′-26′″, termini 28′-28′″,and apertures 30′-30′″. With the appropriate aperture spacing, thesleeves are readily deployed to maintain fluid communication to superiormesenteric, left renal, right renal and celiac arteries and deployingsleeves through tunnels 24-24′″, respectively. Subsequent torevascularization of overlying vessels by a procedure as detailed withrespect to FIGS. 5A-5D, distal ends 206 and 207 are directed into theright common iliac artery and left common iliac artery, respectively,with distal stents 236 and 237 fully deployed within the right and leftiliac arteries to afford a sealing zone without resort to a secondarystent coupled to an inventive endograft with resultant anxiety as to thejoint between the inventive endograft and a secondary stent leaking.

A procedure for repair of a renal aneurysm is preferably performed in astaged fashion to decrease the overall time of the procedure,fluoroscopy contrast agent exposure, and radiation dosage. An exemplaryprocedure for placement of an inventive endograft as a repair includesthe following steps.

1. CT Assessment: Identify patient candidates and obtain diameter andlength measurements. Initial assessment with high resolution helical CTscans will identify patients that are candidates for this procedure. TheCT protocol will be similar to infrarenal stent graft assessments, butextend from the distal descending thoracic aorta to the common femoralarteries. In patient candidates aortic diameters and lengths will bedetermined.

2. Angiography and visceral artery covered stent placement. Diagnosticangiography will provide further anatomic definition, also coveredstents will be deployed in the SMA and the right and left renalarteries. Patient candidates identified with CT will proceed toangiography to assess the status of the SMA and renal arteries. Inaddition, any stenotic lesions of the visceral arteries will be treatedat this time.

3. Endo-graft deployment, mesenteric revascularization, conventionalendograft aneurysm repair. The delivery and deployment of the aorticendograft will utilize the current methods used with infrarenal aneurysmendograft repair. Bilateral femoral artery exposure and left brachialartery access will be used. The patient will be anticoagulated onceartery exposure is obtained.

Endograft deployment: A stiff guide wire is advanced under fluoroscopyinto the proximal descending thoracic aorta from the femoral arterybeing used for delivery of the main aortic component. The main componentis then delivered into the distal descending thoracic aorta fordeployment above the SMA, using the previously placed SMA covered stentas a landmark. The endograft will be oriented by unique radio-opaquemarkers for the renal and SMA branches. Once in position the supramesenteric component will be partially deployed for a length of about2.5 centimeters or otherwise to expose the celiac and SMA upstreamapertures 30′″ and 30, respectively, as shown in lateral view in FIG.5A. The infrarenal portion of the endograft will not be deployed untilmesenteric revascularization is complete to avoid compromising guidewire access to the native mesenteric arteries.

4. Visceral revascularization. Placing the mesenteric endografts willoptimally be performed from the left brachial approach. This will taleadvantage of the visceral artery anatomy relative to the aorta. Usingstandard guide wire techniques a 90 centimeter brachial catheter 90sheath is advanced to the aorta proximal to the endograft. The SMAtunnel will be accessed within the endograft by a marking catheter 92having gradations to assess the required sleeve length needed to extendwithin the endograft and into the branching vessel to which fluidcommunication is to be maintained. The marking catheter 92 will beadvanced through the tunnel into the native aortic lumen and into thenative SMA. A stent is then fed into position spanning a portion of thetunnel 24 through aperture 30 and into the native SMA before sleevestent expansion 94 in FIG. 5B. In FIG. 5A the celiac artery is shownhaving already been spanned by a sleeve stent 93 expanded in tunnel 24′″and extending through aperture 30′″ into the native celiac artery by aprocess as detailed above for the SMA. The order of SMA and celiacartery revascularization is appreciated to be immaterial. Typically, astent has at least 1.5 centimeter coverage into the native artery.Alternatively, the celiac and/or SMA spanning stents are transported upthe given artery into the appropriate sleeve. Proximity to an aneurysmor an involved arterial juncture are instances that are indications thatmay justify the added complexity of arterial stent delivery. Thepositioning of the endograft or the sleeve stent is guided with contrastinjections from the brachial catheter 90.

Subsequent to SMA and optional celiac artery revascularization, as thevisceral first stage of endograft deployment, longitudinal expansion ofthe endograft main body occurs distal from aperture 30. It is noted thatrevascularizing the SMA and optional celiac artery affords a measure offixation to the endograft against torsion associated with succeedingrenal artery revascularization.

This procedure will be repeated for the right and left renal arteries.Once SMA and renal endovascular revascularization is completed theinfrarenal component of the SRE will be deployed. This completes SREdeployment and visceral revascularization.

5. Renal revascularization. FIGS. 5C and 5D are rotated views relativeto the lateral views of FIGS. 5A and 5B to schematically illustraterenal artery revascularization. The brachial catheter 90 and the markingcatheter 92 are employed as detailed above for visceral SMArevascularization to successively revascularize the right and left renalarteries with sleeves 96 and 98, respectively. Preferably, the distal2.5 centimeter section of the endograft main body is retained in acollapsed state during positioning and expansion of sleeves 96 and 98.Thereafter, as shown in FIG. 5D, the distal docking end of the endograftis expanded.

6. Distal joinder. Additional joinder of a secondary conventional stentto the distal end of the endograft then occurs in instances whereadditional length is required to span an aneurysm. A secondary stent isdeployed directly to the distal end or with resort to a vascular cuff.

Patent documents and publications mentioned in the specification areindicative of the levels of those skilled in the art to which theinvention pertains. These documents and publications are incorporatedherein by reference to the same extent as if each individual document orpublication was specifically and individually incorporated herein byreference.

The foregoing description is illustrative of particular embodiments ofthe invention, but is not meant to be a limitation upon the practicethereof. The following claims, including all equivalents thereof, areintended to define the scope of the invention.

1. An endograft for a vessel having a vascular branch extending from thevessel, said endograft comprising: a main body having a wall defining aninternal surface and an exterior surface and adapted to be placed withinthe vessel, the wall defining a single lumen at a proximal end and twodistal ends, and a main body aperture extending from the interiorsurface to the exterior surface above the two distal ends; at least oneexpandable stent secured to said main body; at least one expandablestent secured to each of the two distal ends; and an open tunnel havinga length extending between a mouth and a terminus, said tunnel securedto the interior surface of said main body about the main body aperture,said tunnel secured along the tunnel length to the internal surface atat least one point to provide fluid communication between the interiorsurface and the exterior surface through the main body aperture and withthe vascular branch in proximity to the main body aperture.
 2. Theendograft of claim 1 wherein the vessel is the descending aorta and thevascular branch is the superior mesenteric artery.
 3. The endograft ofclaim 1 wherein said tunnel bifurcates to create a second terminusdefining a second main body aperture.
 4. The endograft of claim 1wherein the tunnel terminus is flush with the external surface of saidmain body.
 5. The endograft of claim 1 further comprising a sleevepositioned partly within said open tunnel and
 6. The endograft of claim1 further comprising at least one additional open tunnel within saidmain body.
 7. The endograft of claim 6 wherein in said at least oneadditional open tunnel are two additional open tunnels.
 8. The endograftof claim 7 wherein the terminus of said open tunnel is positioned onsaid main body such that upon insertion into a subject, the terminusoverlies the superior mesenteric artery and said two additional opentunnels overlie the renal arteries.
 9. The endograft of claim 1 whereinsaid tunnel has an internal diameter of between 6 and 12 millimeters.10. The endograft of claim 1 wherein said tunnel has a length of from 10to 25 millimeters.
 11. The endograft of claim 1 further comprising asecondary stent coupled to said main body.
 12. The endograft of claim 1wherein the two distal ends are positioned to engage the right and leftiliac arteries.
 13. The endograft of claim 1 wherein said tunnel isindependent of an expandable stent.
 14. The endograft of claim 1 whereinsaid tunnel is secured to the interior surface along the majority of thelength of said tunnel.
 15. An endograft for a vessel having a vascularbranch extending from the vessel, said endograft comprising: a main bodyhaving a wall defining an internal surface and an exterior surface andadapted to be placed within the vessel, the wall defining a single lumenat a proximal end and two distal ends, and a main body apertureextending from the interior surface to the exterior surface above thetwo distal ends; at least one expandable stent secured to said mainbody; at least one expandable stent secured to each of the two distalends; and an open tunnel independent of a stent and having a lengthextended between a mouth and a terminus, said tunnel secured to thetunnel interior surface of said main body about the body aperture toprovide fluid communication between the interior surface and theexterior surface through the main body aperture and with the vascularbranch in proximity to the main body aperture.
 16. The endograft ofclaim 15 wherein the two distal ends are positioned to engage the rightand left iliac arteries.
 17. The endograft of claim 15 wherein thetunnel terminus is flush with the external surface of said main body.18. The endograft of claim 15 wherein said tunnel is secured to theinterior surface along the majority of the length of said tunnel. 19.The endograft of claim 15 wherein the terminus of said open tunnel ispositioned on said main body such that upon insertion into a subject,the terminus overlies the superior mesenteric artery and furthercomprising two additional open tunnels that overlie the renal arteries.20. The endograft of claim 15 further comprising a sleeve positionedpartly within said open tunnel and extending beyond the exterior surfaceof said main body into the vascular branch.